Cap for exhaust pipes and the like



June 25, 1946.

CAP FOR EXHAUST PIPES AND THE LIKE Filed Jan. 1, 1943 l 3 3 I u h l l MI E511 HVVENTOR. 5 Pals/N 47- ro/ewEy in which:

Patented June 25, 1946 UNITED STATES PATENT OFFICE car FOR EXHAUST PIPESAND THE LIKE,

s01 R. Rubin, Los Angeles, Calif.

Application January 1, 1943, Serial No. 471,087

. 2 Claims.

, My invention relates to a cap means for exhaus pipes, ventilatingflues, or the like.

One of the principal objects of this invention is to provide a capmeansof this class which will not allow a down-draft in the pipe, flue,or the like, on whichit is aflixed, irrespective of air or appearhereinafter, I have devised a cap means for exhaust pipes, and the like,which has certain novel features of construction, combination, and

arrangement of parts and portions, as will be hereinafter described indetail and particularly set forth in the appended claims, referencebeing hadto the accompanying characters of reference thereon, which forma part of this'application,

Fig. 1 is a fragmentary side elevation of an exhaust pipe or ventilatingflue extending above the inclined roof of a building, and showing myexhaust cap, in a preferred form of construction,

facilitate the illustration; and,

Figs. 3, 4, 5, and 6 are diagrammaticside elevational views of the cap,showing by arrows different air conditions, or different directions ofwind with respect to the cap, and showing the air exhausting capacitiesthereof under such dif ferent directions of the wind.

The exhaust pipe or ventilating flue I is of conventional constructionand extends through and above the roof 2, which is shown in the drawingas inclined, the pipe or flue I being supported on and sealed withrespect to the roof by the usual flashing member or cone 3.

My exhaust cap means is to be applied to the top of such exhaust pipe orfine. In this instance the exhaust cap means is provided with a separatesupporting neck III which may telescope over the top and outside of thepipe Around the end of the skirt extending above the upper end of theneck a distance slightly greater than the distance of the lower end ofthe skirt below the upper end of the neck. The cross-sectional areabetween the neck ill and the skirt I I may be substantially that of thecross-sectional area of the neck, but, as shown, is slightly less thanthe latter. The hood I2, which is of flat cone shape, may beapproximately twice the diameter of the pipe or neck, and also extendsconsiderably be yond the open upperend of the skirt. The circumferentialarea of the opening between the upper end of the skirt andthe hood issubstantially equal to or slightly greater than the crosssectional areaof the skirt, so that the exhaust of the air beyond the upper opening ofthe skirt will not be choked.

The neck H], the skirt I I, and the hood [2 are all shown cylindrical orcircular and are all arranged coaxially, and these elements aresupported in'such relation by a plurality of straps J3, the same'strapsecuring all three elements togethen. Below the open end of the skirt isarranged a disc shaped bafile M, the same being secured to the neck It)by means of brackets 15. The bafile I4 is positioned such a distancebelow the lower end of the skirt II that the cross-sectional areabetween the skirt and the baflle is greater than the cross-sectionalarea between the neck and the skirt. The outer diameter of the baffle I4is also greater than the diameter of the skirt, as shown. The positionsof the baffle l4 below the skirt and the spacing of the-latter outwardlyfrom the neck is such that wind which passes upwardly from below thebaffie in a vertical direction, ora relatively sharp angle to thevertical direction, will be deflected outwardly from suchcap by thebafile. The spacing of the baflle below the skirt and the position ofthe upper end of the neck above the lower end of the skirt is such thata horizontal wind, or wind which makes only a slight angle with suchhorizontal direction, will rather be split and the major portion willpass around the neck. The relation between the several elements is suchthat the lower end of the skirt ll intersects or is positioned slightlybelow the line extending through or between the peripheral edge of thebafiie and the topof the pipe, or so that the lower edge of the skirt ispositioned in such relation to the conical plane which is tangent to theperipheral edge of the ballle and the top of the neck, such plane beingindicated by P in Fig. 1.

Different wind conditions or directions are upper end of the neck to isa skirt II, the upper shown in Figs. 1, 3, 4, 5, and 6, and these areindi- 3 cated, respectively, by A, B, C, D, and E in these figures.

In Fig. l the wind, represented by the arrow designated A, is shown asdirected horizontally from the side. The air will impinge against thepipe or neck 1 below the skirt and will be split and deflected to theopposite sides, and only a small part of the air will rise into theskirt. The air directed above the skirt will pass below the hood fromone side of the skirt to the other. The latter air will cause anup-draft both in the pipe I and in the skirt.

The direction of the wind in Fig. 3 is designated by B, it beingdirected at an angle from the side and from above. The air will impingeagainst the top of the hood and will be deflected as indicated by B Theair directed toward the forward side or portion of the hood will bedeflected downwardly toward the side of the cap, as indicated by 13 andthe principal portion will be directed downwardly past the baflie. Aportion of the air will be directed over the top of the bafile, asindicated by B and will tend to draw air from the bottom of the skirt.The air passing downwardly beyond the edges of the hood, and alsodownwardly from the skirt, will tend to draw air from the top and bottomof the skirt, as indicated by B and B respectively. This will create anupdraft in the pipe or neck.

In Fig. 4, the wind, designated 0, is shown as assuming a downward pathdirectly against the top of the hood. The hood will cause suchdowncurrent to pass by the cap, shown by C creating a vacuum primarilyat the top of the skirt and perhaps a slight vacuum at the bottom of theskirt, as indicated by C and C respectively.

The rarefied condition of the air at both ends of the skirt will causean up-draft in the pipe or neck. Heretofore exhaust caps have been made7 wind, designated D, is at an angle from below. The principal portionof the air will assume a path toward the top of the skirt, as indicatedby D and the air will pass over the top of the skirt to the oppositeside of the hood. Such passage of theair will cause a rarefied conditionat the top of the skirt and produce an up-draft in the pipe "or neck.Since the outer edge of the baille extends beyond the skirt, any 'airpassing between the baflle and the lower end of the skirt will be splitby the pipe or neck and tend to flow around the latter, as indicated b Drather than pass upwardly into the skirt. A small portion of such air,however, may pass upwardly into the skirt and will cause a slightadditional vacuum at the upper end of the pipe or neck and assist in theup-draft therein.

In Fig. 6 of the drawing, the wind is shown as passing directly upwardlyalong the outer side of the pipe. This condition may take place when theexhaust pipe or ventilating flue is located at the side of a steeppitched roof, or when the pipe is located near a parapet wall or in thecorner of such walls. In this instance, the baffle will cause the windto be diverted outwardly and assume a direction indicated by E This willcause rarefied conditions; at the upper and lower ends of the skirt andresult in an updraft in the pipe or neck, as indicated, respectively, byE and E Though I have shown and described a particular construction,combination, and arrangement of parts and portions and have describedparticular theories of action inrelation to different wind conditions, Ido not-wish to belimited to the same, but desire to include in the scopeof my invention the construction, combination, and arrangementsubstantially asset forth in the appended claims. r I

I claim: I

1. In an exhaust cap of the class described, a supporting tubular neckfor the top of an exhaust pipe, a co-axial skirt surrounding and spacedoutwardly therefrom with its upper and lower ends positionedrespectively above and below the opening at the upper end of the neck, ahood positioned and spaced above the upper end of the skirt, a bafllespaced below the lower endof the skirt and extending laterally from theneck, the lower edge of the skirt lying substantially within the conicalsurface extending between the outer edge of the baffle and the upperedge of the neck, and means for securing the neck, skirt, and hood insaid spaced relation.

2. In an exhaust cap of'the class described, a supporting tubularneckfor the top of an exhaust pipe, a coaxial skirt surrounding and spacedoutwardly therefrom with its upper and lower ends positioned respectivelabove and below the opening at the upper end of the neck, a hoodpositioned and spaced above the upper end of the skirt, a battle spacedbelow the lower end ofthe skirt and extending laterally from the neck,the lower edge of the skirt lying substantially within the conicalsurface extending between the outer edge of the bafile and the upperedge of the neck, and means for securing the neck, skirt, and hood insaid spaced relation. w

Y SOL R. RUBIN.

